This has happened a few times and once again its happening in a league game, so I thought I better make sure Im not misunderstanding something.
In game #613666 of league #7134 you'll see that I took the last kill ending the match and scoring a Tac-Vic for my team (allies) awarding me 6 league points, my opponent 3 & so on. My opponent however had outscored me 110-75 in points, but as I shot him down & survived the win seems to go to me and is stated as such.
Yet in my last 10 games list as well as the list of completed league games on the league page it is listed as a win for my opponent, also I noted no change in my league score (this could be my oversight/miscalculation)
Am I misunderstanding something? Perhaps some finer point of the league scoring system

Your opponent outscored you, so he gets the win. He was shot down, so you get the victory. That's how it reads looking at the game, and is how I understood it was supposed to be.